arm64: dts: altera: Remove unused and undocumented "snps,max-mtu" property

Remove "snps,max-mtu" property which is both unused in the kernel and
undocumented. Most likely they are leftovers from downstream.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>

Author: robherring

arch/arm64/boot/dts/altera/socfpga_stratix10_swvp.dts

@@ -63,7 +63,6 @@
 	status = "okay";
 	phy-mode = "rgmii";
 	phy-addr = <0xffffffff>;
-	snps,max-mtu = <0x0>;
 };
 
 &gmac1 {